Sink I/O Devices and Modules

The figure on the right depicts an input sink module.
Note that one terminal of the module is connected to
the DCV common. Now note the input device. One side
of the input device is wired to +VDC. According to
the definition, this input device is connected type
source, (one connection of a souce device or module
is connected to +VDC.) These connections define
another fact, sink modules are wired with source
devices.

A sink module supplies the I/O power supply return
path or the path to the DCV common.

The polarity of a module can always be determined
by looking at how the field devices are wired to
the module. In the figure on the right, since one
side of the field device is wired the +VDC, as stated
above the device is sourcing. Since the field device
is source, then by definition the module must be
sink.

The figure on the right depicts an output sink module.
Note that one terminal of the module is connected to
the DCV common. Now note the output device. One side
of the output device is wired to +VDC. According to
the definition, this output device is connected type
source, (one connection of a souce device or module
is connected to +VDC.) These connections define
another fact, sink modules are wired with source
devices.

A sink module supplies the I/O power supply return
path or the path to the DCV common.

The polarity of a module can always be determined
by looking at how the field devices are wired to
the module. In the figure on the right, since one
side of the field device is wired the +VDC, as stated
above the device is sourcing. Since the field device
is source, then by definition the module must be
sink.